> You have SIMS set for Unlimited mailbox size... but it seems you don't

actually want it to be unlimited. Change it to a smaller size. Or, make
sure the offending users haven't changed their mail client to allowing
email to stay on the server for more than 10 days. Possibly some of those
clients have set it to leave on the server forever (15,000 files in 10
days would be 1500 emails per day... those people must have some pretty
serious email activity if that number is really being collected in 10
days time)

My client (Entourage 11.1 on OS 10.3.9) is set up to delete messages from
the server when they are picked up (leave a copy on server is NOT checked),
yet my account folder had 500+ messages dating back to 2003. (This server is
used in a non-profit outfit, and I do volunteer admin, so I don't get much
mail at all through this system.) Shouldn't the server be dumping the files
associated with messages that have been downloaded to the client? Seems odd
that in my case it's still hanging onto them.
--
Dave

I have seen similar on my SIMS.

The problem usually is related to malformed email headers - in Eudora, such emails are marked with an "X" indicating incomplete downloads. Several of the lists I'm on routinely pass emails which don't get auto-deleted from the server.

Perhaps you could write an applescript which would go into each user folder daily and delete anything older than 10 days (or maybe 15 to be safe)?